From the DE 199 29 093 C2 a rotor system for a bicycle for bearing, rotatably by 360°, a fork and for the transmission of actuations of brake cables is known, with a rotor unit, arranged in the area of the bearing of the fork, which is movable on the whole relatively to the fork in axial direction and which comprises at least two transmission elements that are rotatable relative to one another, wherein the transmission elements at least in radial direction are surrounded by a housing.
Another rotor system, which also makes possible a 360° turn of the fork, is known from WO 2012/005610 A2. A first Bowden control cable is guided from the handlebar into the fork steerer. At the end of its core a bar is fixed, which protrudes out of the fork steerer through fork steerer openings, where it is taken up by the first transmission element. The arrangement of the core of the second Bowden cable leading to the back wheel at the upper ring-shaped second transmission element is done by means of a fixture bent at a right angle screwed onto the transmission element, in whose radially outwards extending area, which is provided with a slotted receiving opening for introducing the core, the thickened end of the core is suspended. At the housing a comparable overturned brake arm is screwed, which with its area extending outwards in radial direction, that is formed according to the above mentioned fixture, adheres to the first fixture from the bottom and supports it. This kind of arrangement also corresponds to the technical realization of DE 199 29 093 C2, in which the arrangement of the cores of the Bowden mechanisms serving as brake cables is only illustrated schematically.
In FR 571 408 a transmission mechanism is known, which uses bars and levers. In the stem a crank is mounted, at which a bar introduced into the fork steerer is articulated, which in the area of the lower end carries a bar that protrudes out of the fork steerer through fork steerer openings. A first transmission element sits on the bar. The second transmission element is formed bifurcated, with the shaft articulated at the transition from the head tube to the lower tube and resting with the fork peaks on the first transmission element. At the shaft of the second transmission element a Bowden control cable is fixed, which is guided further through the lower tube. The transmission elements do not form a unit, but perform different movements when a braking is executed.